The Internet is not a physical or tangible entity, but rather a giant network which interconnects innumerable smaller groups of linked computer networks and is thus a network of networks. In 1981, fewer than 300 computers were linked to the Internet, and by 1989 the number stood at just under 90,000 computers. It is estimated that as of 1999, approximately 200,000,000 users, including personal computers and host computers, are connected to the Internet. Unfortunately, the nature of the Internet is such that it is very difficult if not impossible to determine the size at any given time since it is growing minute by minute.
The Internet had its origins in 1969 as an experimental project at the US Advanced Research Project Agency (ARPA) and was called ARPANET. ARPA networked computers and computer networks owned by the military defence contractors and university laboratories conducting defence related research. The network later allowed researchers across the country to access directly the extremely powerful super-computers located in few key universities and laboratories. ARPANET went far beyond its research origins in the United States to encompass universities, corporations, and many people around the world, and came to be called the Internet. No single entity, academic, corporate, governmental, or non-profit organization administers the Internet. It exists and functions because hundreds of thousands of separate operators of computers and computer networks use common transfer protocols to exchange information with other computers. There is no centralized storage location or communications channel for the Internet, and it would not be technically feasible for a single entity to control all the information conveyed on the Internet.
The Internet's open distributed decentralized nature stands in sharp contrast to earlier information systems. Private information services such as WEST LAWJ, LEXUS/NEXUSJ and DIALOGJ contain large store houses of information that may be accessed from the Internet with the appropriate passwords and access software. However, these various databases are not linked together in a single whole as is the World Wide Web.
The World Wide Web has become a popular medium because of its open distributed and
easy-to-use nature. Rather than requiring a user to purchase new software or hardware and to learn a new kind of system for each database of information to be accessed, the web environment provides an easy means of access to a wide variety of information sources. The openness of the web also makes it easy for disseminators of information to reach their intended audiences without regard to the type of computer software that may be used by the potential user.
Many organizations now have Ahome pages@ on the web. The home page will typically contain links that guide the user to other sources of information about the organization. The links may lead to a different location in the same document, or to different documents on the same website.
Links may also take the user from the original website to a different site located on another computer connected to the Internet. It is these millions of links between websites that make the web such a powerful tool for sharing knowledge.